Hydraulic riveting apparatus



Jan. 21, 1941. w MEIER 2,229,218

HYDRAULIC RIVETING APPARATUS v Filed March 30. 1937 2 Sheets-Shut l .zo @3" f' y IN VENTOR. WMU/)M /VE/f/E ATTORNEY.

Jan. 21, 1941. w. MEIER 2,229,218

HYDRAULIC RIVETING APPARATUS Filed uar'c'n so, 1937 2 sheets-sheet 2 5 l .Ml- Q7 I W/u/Aw /Vf/e In c ATTRNEY.

Patented Jan. 21, 1941 UNITED STATES PATENT OFFICE HYDRAULIC RIVETING APPARATUS Application March 30,

4 Claims.

This invention relates to new and useful improvements in hydraulic riveting apparatus.

An important object of the invention is to pro- Vide an entirely portable and self-contained hydraulic riveting apparatus including the pump and source of power which can be readily moved from place to place. l

Another important object of the invention is to locate all uid control points in a single valve mechanism installed in the uid reservoir to reduce the number of external high pressure piping and pressure joints.

Another object of the invention is to provide a control valve with means for regulating the length of piston or ram stroke upon return movements'.

Other objects and advantages of the invention will become apparent during the course of the following description.

In the accompanying drawings forming a part of the application and wherein like numerals are employed to designate like parts throughout the several views:

Fig. 1 is a side elevation of the portable unit including pump, reservoir and riveting ram and anvil; the cylinder and ram being shown in section for clarity.

Fig. 2 is a vertical section of the control valve with parts thereof shown in position to elevate the piston ram,

Fig. 3 is a corresponding section of the control valve showing the parts thereof in position to cause protection of the ram,

Fig. 4 is a fragmentary top plan of the control valve and support therefor. n

Referring now more particularly to the drawings and wherein for the purposes of illustration, the form of device at present vpreferred is fully illustrated, the letter R. designates in general the hydraulic riveting ram and anvil, the latter being in the form of a yoke or horn I having a rivet set and work supporting free end 2. The other end 3 of the yoke isvprovided with an aperture 4 through which projects a reduced ram guide 5 threaded at its lower extremity for the reception of a clamping and lock nut means 6 whereby the guide is very rigidly secured to the anvil I.

This ram guide 5 is an integral extension of a detachable bottom 'I of a hydraulic cylinder 8 and is provided with a packing S seated in the recess of the detachable bottom through which the ram I U extends to be slidably mounted in the guide 5.

The upper end of the ram I is provided with an integral enlargement Il detachably and se- 1937, serial No. 133,926

(c1. rsa-52) cur-ely fastened to an enlarged piston head I2 which divides the cylinder 8 into upper and lower pressure chambers I3 and I4 respectively. The cylinder at its lower end is externally threaded for engagement with the internally threaded lange of the detachable bottom and this joint is packed with a packing I securely held` at the joint by a flanged clampingring I6 overlapping the flange of the detachable bottom and a locking collar I1.

In order that the riveting horn and ram can be handled with facility and shifted from one position to another, this unit is suspended from overhead with a suspension yoke I3 having the lower ends of its arms pivotally secured to opposite sides of the riveting horn. 'Ihis suspension @ke I8 is supported by a cable I 9 passing over a series of pulleys and having a counter weight 2l attached to one end of the cable so that the riveting horn-canbe easily raised, lowered and held yin, position with practically little effort on the part of the operator. I

In order to conduct operating fluid to ,the chambers I3 and I4 above and ybelow the piston 5 I2, a high pressure flexible conduit A is secured r. to the upper end of the cylinder to communicate with aport 21T/leading to the upper chamber I3 and a similar high pressure flexible conduit B communicates with a port 23 in the bottom of the 3o cylinder to form communication with the lower 'l chamber I4.

In order to operate a control valve, to be presently described, an electric lreciprocating switch 24 is mounted at the side of the cylinder k8 in a 35 manner. forming a handle by which the riveting horn can be handled with facility. The electrical conductors from the switch 24 to a solenoid 25 having a reciprocable core piece 26 are carried in a flexible conduit 2l. 40

This solenoid for actuating the main control valve is mounted upon posts 28 arising from a supporting bar 29 mounted on top of a portable tank or reservoir 30. Y

This portable tank or reservoir 30 is supported 45 by legs 3l and has an electric motor 32 mounted with its armature shaft vertical and extending into a rotary pump 33 submerged in the liquid in the reservoir. An electric switch 34 positioned on the reservoir is connected to the motor 32 for 50 starting and stopping the same. The pump is provided with the usual inlet 35 and a discharge conduit 36 connected to a control valve casing 3l submerged in the liquid of the reservoir and supported from the bar 29 across the top thereof. 55

Pressure and return conduits A and B respectively to the ram are connected to the valve casing below the level of the liquid in the reservoir as shown in Fig. 1. This valve casing 31 is provided with a central bore 38 extending all the way through the top and bottom of the lcasing and in which is disposed an elongated valve sleeve 39 to form a central reversing valve chamber 40. This sleeve may be slipped into either end of the bore and is held in proper relation therewith by means of an upper bushing 4| having a threaded extension to be screwed into the top of the casing and against the upper end of this sleeve. The lower end of the sleeve 39 is engaged by the threaded extension of a collar 42 screwing into the valve casing. This collar is provided with an opening 43 having sufficient clearance with the stem 44 of a valve body 45 to permit the passage of liquid from the valve casing into the liquid of the reservoir. This stem 44 projects a substantial distance below the valve body and is provided with a head 46 against which one end of a compression coil spring 41 abuts and with its other end abutting the collar 42 in order to normally retain the valve body 25 in its lowermost position as shown in Fig. 2.

The valve body is in the form of a spool with spaced closure portions 48 and 49. The upper end of the valve body is provided with an extension 50 slidably engaging the bushing 4| and having an apertured upper end to be pivotally connected with the lower end of the core piece 26 of magnet 25. The upper end of valve sleeve 39 and the valve casing are provided with a port 5| which is always located `above the upper closure portion 49 of the valve. A short distance below this port, is a second .port 52 which leads toward the pressure conduit A. The upper closure portion 49 of the valve is adapted to slide across this port 52 so that when it is in the position shown in Fig. 2 the return fluid from the upper chamber I3 of the ram will pass out through the port 5| and back into the reservoir. Also, in this position, the port 52 is cut off from the pressure from the pump.

Below this port 52 and in the opposite side of the valve sleeve is a port 53 which leads toward the intake pipe 35 from the pump and the closure portions 48 and 49 of the valve are always arranged upon opposite sides of this port 53. Below the port 53 and on the side of the valve sleeve in which the port 52 is positioned, is a fourth port 54 adapted to be controlled by the lower closure portion 48 of the valve and leading to the conduit B in communication with the lower chamber I4 of the ram.

When the reversing valve is in the position shown in Fig. 2, the ram I9 is elevated since the ports 53 and 54 are placed in communication with the conduit B and ports 5| and 52 are in communication to return the fluid from the conduit A leading to the chamber above the ram back to the reservoir. Upon depression of the switch button of switch 24the core 26 of the solenoid is moved into the magnetic winding to elevate the valve 45 to the position shown in Fig. 3 and upon release of the switch in breaking of the current, the spring 41 automatically withdraws the core from the solenoid and places the valve body in the position shown in Fig, 2, which is in its normal position.

To communicate the port 52 with the conduit A, a lateral extension port 55 is provided in the valve casing. A passage 56 provides communication between the port 55 and the upper end of a pressure and valve chamber 51 which is formed by inserting a valve sleeve 58 within a bore paralleling the bore for the reversing valve just described. This valve sleeve 58 has a closed lower end 59 provided with an opening 60 and is externally threaded for attachment to the valve casing as shown. This valve sleeve and the valve casing are provided with registering ports 6| opening into the reservoir. A pressure responsive valve 62 is slidably mounted in the sleeve and is provided at its upper end with an enlarged head 63 and at its lower end with a smaller head 64 operating in the smaller end of sleeve 58. These heads provide the valve with spool form, so that the chamber between these heads is always in communication with the lower port 54 in valve sleeve 39 by means of registering ports E5 in the sleeve 58 and valve casing, and also communicates with the conduit B by means of a retraction port 65 provided in the sleeve 58 opposite port 65. The exhaust port 6| is at all times cut oi from communication with port 55 by the upper head 63 which also controls the opening and closing of this exhaust port with respect to the conduit B and which controls retraction of the ram or the length of its retracting stroke. The position of this valve 62 is controlled by the pressure of uid below the upper head 63 as well as by pressure of fluid in extension port 55 entering valve sleeve 58 through the port 56. This latter port is controlled by a needle valve B1 screwed into the top of the valve casing as shown, so as to control the amount and pressure of fluid which is to be effective upon the upper head 63. In other words, the valves 52 and 61 are provided to regulate the length of the stroke of the ram during retraction, and to regulate the length of time the load is upon the pump. With this arrangement, pump pressure is relieved upon the ram completing the desired length of upstroke, and overheating of the liquid medium and leakage due to maintained high pressures is avoided.

The needle valve 61 is always open to various degrees when operative, and its range of movement is very restricted. In fact, its full operative, open position is about 1/32 of an inch from the walls oi port 5B. The amount the valve 61 is opened or spaced from its port 56, controls the time interval the pump pressure is on and consequently the length of the upstroke of the ram. 'Ihe more the valve 61 is open, within certain limits, the shorter the ram stroke; and the less its opening, the longer the ram upstroke is. The maximum opening of the valve 61 is very slight due to the small volume of the valve chamber 51 as compared with the volume or capacity of the pump, so as to cause opening of the exhaust portl by the valve head 63, only after suiiicient pressure is built up and the ram has almost completed its upstroke. This opening of port 6| near the end of the upstroke, naturally cuts off pressure to the ram to prevent slamming of the ram piston |2 against the top of its cylinder. In eiiect, this slow or retarded raising of valve 62 and opening of exhaust port 6| provides somewhat of a cushion and retards opening of the exhaust port unit the ram has almost reached the limit of retraction or upstroke.

The complete cycle of operation is as iollows: Bearing in mind that if a longer upstroke of the ram is desired, the needle valve 61 is moved nearer its closed position with reference to the port 56 so as to greatly restrict exhausting the chamber 51- ofuid 'which means a slower opening of exhaust port 6l to relieve the ram from further pressure by the fluid under pressure being returned'to the reservoir through the eX- haust port 6|. When the ram Il) is at rest, and retracted as shown in Fig. 1, the magnetically controlled reversing valve 45 is in the position shown in Fig. 2 so that the pump 33 is normally pumping fluid throughr the lower retraction port 54 rand back into the reservoir through the exhaust port 6 l.

To cause a downstroke of the ram i5, the switch 24 is operated to energize the magnet 25 and lift the reversing valve 45 against the tension of spring 41 to the position shown in Fig. 3. This movement of the valve closes port 54 to the iiow of liquid under pressure from the pump and directs it through port 52 into extension conduit A and while passing through passage 55, some of the liquid enters through port 56 into chamber 51 to move pressure valve 62 down to the position shown in Fig. 3 thereby closing exhaust port 6l and causing a return flow of liquid under pressure from the ram coming through retraction conduit B to exhaust into the reservoir through the ports 54 and 43.

When the operator removes his nger from switch 24, the spring 41 will immediately return the reversing valve 45 to the position shown in Fig. 2, whereupon port 52 will be closed to the pump pressure while 54 is open thereto to permit it to pass to the retraction conduit B to cause the ram to move up or be retracted. During this retraction, the pressure is building up under the valve head 63 gradually causing it to raise and push uid in chamber 51 out through port 56 and thus to exhaust port 5l until the ram l has almost completed its upstroke at which time the valve head 63 will have moved up to uncover the exhaust port 6| so as to relieve the ram and pump from further pressure due to its exhaust through port 6| back into the reservoir. By slightly opening the needle valve B1 further, the upstroke of the ram I0 can be shortened so that it will come to rest at any desired point above the anvil 2, whereby to obtain any desired clearance between ram and anvil best suited to the work in hand while maintaining loW pressure conditions throughout the apparatus as much as possible and to reduce to the minimum the volume of liquid to be pumped to cause the ram to cooperate with the anvil for the desired riveting operation.

In order to control the amount of fluid pressure delivered to the ram by the control valve, the valve casing 31 is provided with a pressure regulating valve 68 in the form of a spool having an upper head 69 and a lower head 10 of smaller area operating in a sleeve 1I having a main bore 12 for the upper head and a smaller counter bore 13 for the smaller head 10; or the sleeve for the lower head may be separate from the sleeve 1I. The upper head 69 is adapted to control and normally close an exhaust port 14 in the sleeve 1I in valve casing which serves to exhaust iiuid from the valve casing when the pressure of fluid therein exceeds a predetermined amount. Below this exhaust port, the sleeve 1l is provided with diametrically disposed ports 15 which are placed in registration with the inlet pipe 35 from the pump and a port 16 in the valve casing which is in registration with the inlet port 53 of the reversing valve 45. An opening 11 is provided in the valve casing to communicate the reservoir with the space beneath the lower valve head to relieve resistance to the movement of the Vvpressure regulating valve 68.

In' order to regulate the 'amount of fluid pressure necessary to elevate the valve 68 and open exhaust 'port 14,'a compression spring 18 engages the upper head 59 ofthe valve while its upper end engages a follower 19 adjustable longitudinally yin, a closed springv cage 85 screwed into the valve casing andv abutting'the upper end of valve sleeve 1l to retain it yin fixed position. A regulating screw 8l is threaded through the upper end of the cage 82 to engage the follower 19 to adjust the load on the spring 13 as desired. Whenever the pressure developed by the pump within the control valve casing exceeds a predetermined loading of thespring 1B the valve 68 will move upwardlyto open the exhaust port until the reduced pressure' of the fluid in the valve'casing permits the spring to-return the valve head 69 to a position closing the exhaust port 14.

It is to be understood that various changes in the size, shape and arrangement of parts may be resorted to without departing from the spirit of the invention or the scope of the appended claims.

I claim:

l. The combination with a double acting ram and its cylinder, of a constantly operating pump, a reservoir from which liquid is directly delivered by the pump to the ram, a reversing valve connected with the pump and reservoir and having pressure and retraction conduits alternately communicable with the pump to alternately connect opposite ends of the ram cylinder with pump pressure, a pressure chamber always having communication with said conduits, and having an exhaust port leading to the reservoir closed to one conduit and communicable with the other conduit, and a diierential pressure operated valve in said pressure chamber responsive to pressures in the extension and retraction conduits and adapted to be moved by the pump pressure in said retraction conduit to open said exhaust port to the reservoir to connect the retraction conduit to said reservoir after a predetermined retraction of the ram, and a regulatable valve controlling communication between the extension conduit and the pressure chamber of the pressure operated valve to control the length of stroke of the ram.

2. A hydraulic ram control comprising a source offluid pressure, a control valve casing having l conduits for conveying liquid under pressure to the top and bottom of the ram for extending and retracting the same, a reversing valve in said valve casing which in one position directs iiuid under pressure to the retraction conduit and in its other position directs fluid under pressure to the extension conduit, a pressure chamber in said valve casing in communication with said conduits and having an outlet port between its ends always closed to said extension conduit and communicable with said retraction conduit, a differential pressure operated valve responsive to pressures in said extension and retraction conduits in said pressure chamber having a body covering said outlet port to the extension port in all positions of said pressure valve and adapted to uncover said outlet port to said retraction conduit when a predetermined pressure is built up in said retraction conduit, and an adjustable valve controlling the communication between said pressure chamber and the extension conduit.

3. A hydraulic ram control comprising a source of fluid pressure, a control valve casing having conduits for conveying liquid under pressure to Cil the top and bottom of the ram for extending and retracting the same, a reversing valve in said valve casing which in one position directs uid under pressure to the retraction conduit and in its other position directs fluid under pressure to the extension conduit, a pressure chamber in said valve casing in communication with said conduits and having an exhaust port between its endsalways closed to said extension conduit and communicatable with said retraction port, and a dash pot valve in said pressure chamber responsive to pressures in said extension and retraction conduits for opening the exhaust port to the retraction port when a predetermined pressure exists in the latter.

4. A hydraulic ram control comprising a source of uid pressure, a control valve casing having conduits for conveying liquid under pressure to the top and bottom of the ram for extending and retracting the same, a reversing valve in said valve casing which vin one position directs iiuid under pressure to the retraction conduit, and in its other position directs fluid under pressure to the extension conduit, a pressure chamber in said valve casing in communication at opposite ends with both of said conduits and having an exhaust port between its ends always closed off from communication with said extension conduit and communictable with said retraction port, a differential pressure operated valve in said pressure chamber covering said exhaust port to the extension conduit in al1 positions of said pressure operated valve and adapted to uncover said exhaust port to the retraction conduit when a predetermined pressure is built up in the retraction conduit, and an adjustable valve controlling WILLIAM MEIER. 

